<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1>this is static </h1>
    <script>
        let a = {
            val:0,
            toString(){
                a.val++;
                return a.val
            },
            valueOf(){
                a.val++;
                return a.val
            }
        }
        console.log(+a)
        console.log(+a)
        console.log(+a)
        if(a === 1 && a===2 && a===3){
            console.log("heihei")
        }
    </script>
</body>
</html>